Handheld transducer operating state indicator

ABSTRACT

A handheld magnetic transducer comprises a gun-shaped housing having a directional arrow on one surface. The arrow is illuminated by a light within the housing indicating the operating state of the transducer as determined by a signal device. The housing has dimples in opposed side walls for ease of grasping. The armature is in two parts. Each part has a T-shaped portion the crossbars of which overlap. The armature is inserted within the bobbin and is resiliently held at the crossbars to lock into position with a shim. The bobbin front wall in combination with the armature and shim form the muzzle or reading end of the transducer and has a substantially frustro pyramidal shape. The armature-bobbin structure is held in place by fingers which form a part of the transducer housing. The wires from the coil are secured to clips. The clips or terminal are U-shaped members spring retained on arms of the bobbin. The clips each have a flange portion for engaging an aperture in the arm. The reading portion of the transducer is hemispherical in shape with the gap defining an arc thereon such that the transducer is capable of rotation or positioning about one of three axes while moving relative to a record.

United States Patent Kamenir 1 [4 1 June6, 1972 [s41 HANDHELD TRANSDUCEROPERATING STATE INDICATOR [21] Appl.No.: 862,608

[52] U.S.Cl. ..l79ll00.2C, 35/35 C [51] lnt.Cl ..G1lb5/10,Gl lb 19/16[58] FieldoiSearch...' ..l79/100.2 C, 100.2T, 100.2 R;

35/35 C; 235/6l.l I E; 340/149 A, 146.3

[56] References Cited UNITED STATES PATENTS 5/1947 Morton et a1..235/61.1l E

4/1951 Frost ..35/3$ C 2,822,425 2/1958 Hicks ..35l35 C 2,936,342 5/1960Kallmann ..35/35 C 3,224,782 12/1965 lsemura ..274/ 14 3,416,241 12/1968Weitzner ..35I35 C [57] ABSTRACT A handheld magnetic transducercomprises a gun-shaped housing having a directional arrow on onesurface. The arrow is illuminated by a light within the housingindicating the operating state of the transducer as determined by asignal device. The housing has dimples in opposed side walls for ease ofgrasping. The armature is in two parts. Each part has a T- -shapedportion the crossbars of which overlap. The armature is inserted withinthe bobbin and is resiliently held at the crossbars to lock intoposition with a shim. The bobbin front wall in combination with thearmature and shim form the muzzle or reading end of the transducer andhas asubstantially frustro pyramidal shape. The armature-bobbinstructure is held in place by fingers which form a part of thetransducer housing. The wires from the coil are secured to clips. Theclips or terminal are U-shaped members spring retained on anns of thebobbin. The clips each have a flange portion for engaging an aperture inthe arm. The reading portion of the transducer is hemispherical in shapewith the gap defining an arc thereon such that the transducer is capableof rotation or positioning about one of three axes while moving relativeto a record.

4 Chin's, 14 Drawing Figures PATENTEDJUH s 1912 SHEET 1 OF 3 INVENTORMELVIN KAMENIR PATENTEDJUH SE72 3 668 333 SHEET 3 OF 3 F' IG. 9Q. IPRIOR ART Fl 6. lOo. m

INVENTOR MELVIN KAMENIR BY I ML)? 7; 14 (MM ATTORNEY BACKGROUNDOF THEINVENTION This invention relates to transducers and more particularly tocomponents thereof.

In the recording onto. or reading from a magnetic record, such as amagnetic tape, card, or the like with electromagnetic transducersof theprior art, it is necessary to maintain correct spacing and positioningof the transducer with respect the record. As is well known in the art,electro-magnetic transducers are. generally constructed of one or morepole pieces made of iron, ferrite, or the like and fashioned into a,generally ring-shaped body. The pole pieces are either cut or formedsuch that two abutting faces thereof are parallel and closely spaced butdo not touch. This resulting space, termed the, gap, is required forboth the reading and recording functions. The gap may be filled with airor some other material having a lower permeability than the surroundingpole pieces. As a .result, flux passing from the pole pieces to the gapmaterial is caused to fringe and strike the magnetic record placedclosely adjacent the transducer. In this manner recording ispermitted totake place. In a similar manner, the gap is used to sense the fluxsurrounding a magnetic area of a magnetic record and permit itsintroduction into the pole pieces which conduct the flux to a pickupcoil for conversion to a read current.

The amount of read current available will be dependent upon the originalstrength of the magnetized area of, the magnetic record, the materialsof the pole pieces and gap, and the shape, position, and spacing of thegap with respect to the record media. Increasing the spacing between thegap and the magnetized area will reduce theflux reaching the transducerthus reducing the read current. Further, any angular change in theposition of the gap with respect to the recordmediafrom the requiredperpendicular position will effectively increase the gap to mediaspacing and decrease the received flux. Skewing of the position of thegap from its normal position, perpendicular to the lines of flux, mayintroduce spurious signals from adjacent recorded areas, and decreasethe available flux.

In order to minimize positioning errors of the type described above andincrease the effective flux employed to produce the reading current, thepath of movement of the record is carefully controlled and thetransducer is rigidly mounted to maintain desired spacing and alignmentwith the magnetic record media. Such rigid mounting is also necessaryfor the transducer during recording because alignment errors reduce theflux reaching the media and thus reduce the recording strength andenlarge the recording area. With this requirement for rigid mounting itis not possible to record and read magnetic records with a transducerwhich is manually positioned by an operator with respect to a record.

Numerous types of handheld transducers have been suggested. Generally,these transducers are pen-shaped. One such example is disclosed by Frostin U.S. Pat. No. 2,548,011. Penshaped transducers have a majordisadvantage in that the user may tire of holding same and that thepen-shape may slip. In addition orientation may prove exceedinglydifficult, especially where the transducer lacks means for orientationwith respect to a record.

It is well known to use two sections of an armature in forming acompleted transducer. Such devices have been disclosed by Joanou in U.S.Pat. No. 3,105,965 and Ferber in U.S. Pat. No. 2,785,838. In sucharrangements, however, the armatures must be held together by complexgripping members such as clamping blocks or the like. Such combinationsmake for expensive and complex assemblies.

SUMMARY OF THE INVENTION A handheld transducer housing comprises threewalls. The first wall has a surface disposed in a first imaginary planeand is adapted to accommodate a first finger of the hand of the user.The second wall has a surface disposed in a second imaginary planespaced from the first imaginary plane'and is adapted to accommodate thesecond'fmgerwhich is adjacent a second finger of the user. The thirdwall has a surface intersecting the first and second surfaces andadapted to accommodate a third finger, adjacent the second finger, ofthe user.

A handheld transducer housing comprises means fortransducing theinformation from a record. The transducing means is substantiallyresponsive upon beingmoved proximate to the record in at least onepredetermined direction. The housing .has indicating means disposed inthe housing for indicating the predetermined direction.

A handheld transducer housing comprises transducing means within thehousing fortransducing a signal, the housing having at least two wallseach having surfaces lying in an imaginaryplane and each of the wallshaving therein depressions for accommodating the fingers of the hand ofthe user.

An electromagnetic transducer of the type having an armature. Thearmature has a coil about it. The transducer is adapted for use with amagnetic record, the record having lines of flux arranged in an intendedreading path. The transducer comprises at least one reading head affixedto the armature, the reading head having a substantially hemisphericalreading portion.

An armature for anelectrornagnetic transducer comprises two members.These members have generally enlarged portions. The enlarged portionsare .placed in proximity such that the members in combination comprisethe armature.

A bobbin for an electromagnetic transducer. The bobbin has a coremounted assembly for holding wire thereon. In addition it, has means forsupporting an armature and includes means for engaging a shim.

An electrical terminal or clip for use with a bobbin of anelectromagnetic transducer. The clip is substantially U-shaped havingthree walls. The first and third walls being inclined to have oneanother to be spring loaded into assembly with the bobbin.

A handheld transducercomprises a housing and means for illuminationwithin the housing for indicating an operating condition of thetransducer. A housing comprises means for transducing the informationfrom a record. A transducing means within the housing is substantiallyresponsive upon being moved proximate the record in at least onepredetermined direction. The housing has indicating means disposed insaid housing for indicating the predetermined direction and theilluminating means for indicating the operating state of the transducer.

A handheld magnetic transducer comprises a gun-shaped housing, a bobbinwithin the housing, an armature within the bobbin and extending througha laterally extending wall of the bobbin. The armature and the wallforming the muzzle end of the housing. An electrical cable fortransmitting information from that transducer is disposed within hehousing and extends from the handle end thereof.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of atransducer constructed in accordance with the invention;

FIG. 2 is an exploded perspective view of a bobbin, shin, armature, andelectrical connectors constructed in accordance with the invention;

FIG. 3 is a sectional view of the transducer of FIG. 1.

FIG. 4 is a partial sectional view of the transducer of FIG. 3 takenthrough lines 4-4;

FIG. 5 is an elevational view looking into the transducer of FIG. 3 withone wall of the housing removed;

FIG. 6 is an elevational view of the bottom or transducing end of thetransducer of FIG. 3;

FIG. 7 is a perspective view of the transducer of FIG. 1 in use;

FIG. 8 is a perspective view of a prior art magnetic transducer;

FIGS. 9a and 9b are schematic views of a prior art transducer;

FIGS. a, b, and c, are perspective views of the transducer of thisinvention disclosing several types of movement thereof; and

FIG. 1 l is a section taken on line 1 1-ll of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Disclosed herein is anelectromagnetic transducer to be used in conjunction with magnetizablerecord bearing media. This transducer is so designed as to be manuallypositionable with respect to a record. Thus, the transducer may be movedwithout special apparatus for guidance or control with respect to therecord bearing media.

The magnetic transducer 10 (as shown in FIG. 1) has therein a bobbin 12(FIG. 2) which may be constructed of plastic, hard rubber, or otherinsulating materials.

The bobbin 12, as commonly used in the art, retains in place a coil ofwire 14 (shown in phantom in FIG. 2 and in section in FIGS. 3 and 4).The coil 14 serves as a means for having induced therein an electriccurrent by flux in an armature. It will be understood that the coil 14may have any shape configuration as is known in the art.

The bobbin 12 is substantially spool-shaped in its construction havingtwo flat, opposed end walls 16 and 18. Disposed between the end walls 16and 18 and holding them rigidly apart is a rectangularly shaped coremember 20. The coil 14 is wrapped about the core in a manner commonlyknown in the art. Extending through the end walls 16 and 18 and the core20, is a bobbin aperture 22. The front end wall 18 has a surfaceperpendicular to the core 20 which is substantially frustro pyramidal inshape 24.

A shim aperture 26 (see FIGS. 3 and 4) extends perpendicularly from thebobbin aperture 22 into the frustro pyramidal front end 24 of the frontend wall 18 of the bobbin 12.

The rear end wall 16 of the bobbin 12 has extending upwardly therefromand substantially parallel with the axis of the bobbin aperture 22 twoarms, 28 and 30. These arms 28 and 30 form a contiguous part of thebobbin 12. The first arm 28 has therein two apertures, 32 and 34,adapted to receive screws. The second arm 30 has a similar aperture 36.In addition, adjacent each of these apertures 32, 34, and 36 are flangeretaining insets. Only one 38 is visible in FIG. 2.

On the first am 28 separating apertures 32 and 34 is a laterallyextending ridge 40 made of insulating material. In the preferredembodiment this ridge 40 is molded as part of the arm 28. The ridge 40may be equidistant between the apertures 32 and 34. The function of theridge 40 is more fully described below.

The handheld magnetic transducer 10 employs the use of a novel set ofclips 42. The clips 42 are of substantially U- shaped construction,having rectangularly shaped side walls 44, 46, and 48. The first sidewall, 44 has an aperture 50 therein, the function of which is more fullydescribed below. The second side wall 44 forms the base side of the Uconfiguration of the clip 42. The third side wall 48 has a tab 52 whichextends laterally from the third side wall 48 and parallel the bottomwall 44 of the clip 42. The tab 52 has a substantially T- shaped headportion 54. This tab 52 may be cut or punched out of the third side wall48 leaving therein a T-shaped aperture 56.

At the free end of the third side wall 48 is an L-shaped flange 58. Thisflange 58 extends parallel to the second side wall 46 and inwardly ofthe U-shaped clip 42. The U-shaped clip 42 may be constructed of aconducting material, such as copper, or spring steel. The side walls 44and 48 of the U- shaped clip 42 incline inwardly toward one another. Inplace on the arms 28 and 30, the L-shaped flange 58 resides in theflange retaining insert 38. The apertures 32, 34, and 36, respectively,are each in alignment with the apertures 50 and 56 of each of the clips44. The side walls 44 and 48 act as springs to hold the clips 42securely to the arms 28 and 30.

The tab 52 is designed for the attachment, by solder or otherwise, ofwires 60 (FIG. 5) from the coil 14. The head 54 of the tab 52 serves toprevent the wires 60 soldered thereto from slipping off. The bobbin 12,has in its rearward wall 16 a notch 62 through which are placed thewires 60 of the coil 14. The ridge 40 serves to insulate and separatethe clips 42 on the first arm 28 from coming into contact with oneanother.

The handheld magnetic transducer 10 employs a shim 64. The shim 64 ofthis invention has an upwardly extending boss 66. As is commonly knownin the art, the shim 64 is made of a nonmagnetic material and may beapproximately 5/1000 of an inch in thickness. The boss 66 may be made bymeans of punching into a die or molding.

The general function of a shim is to keep the reading head of anarmature in place. The broader functions of the shim of this inventionwill be more fully described below.

As may be seen from the drawing, the shim 66 is substantiallyrectangular in shape, having one side of which being surmounted by afrostro triangularly shaped portion 68. The shape of the shim 64 isdesigned so as to conform with the shape of the reading head, more fullydescribed below.

The shim 64 which, except for the boss 66, is essentially thin and flat,is within the bobbin apperture 22 in the frustro pyramid portion 24 ofthe bobbin 12 with the boss 66 extending into the shim aperture 26.

The armature of an electromagnetic transducer serves to cause the fluxobtained from a record to flow therethrough and pass a coil. The fluxinduces a current in the coil.

The armature 70 of this invention comprises two parts 72 and 74. Thearmature 70 may be constructed of materials commonly known in the arthaving high permeability. For example, the armature 70 may be made of amaterial made of 79 percent nickel, 5 percent molybdenum, and 16 percentiron. The shim 64 can be made of plastic. In the present embodiment theshim 64 is made of beryllium-copper. The shim 64 can also be made of anonmagnetic stainless steel so that it can withstand wear. The firstpart or section 72 of the armature (FIG. 2) has a T-shaped constructionwith the leg 76 thereof extending at an obtuse angle, downwardly withrespect to the crossbar 78 of the T. The leg 76 terminates with an innergap taper 80 (FIG. 5), which is a common method of making the readingportion of an armature.

The crossbar 78 has a small rectangularly shaped section 82, extendingin the same plane as the crossbar 78 and outwardly therefrom and opposedto the leg 76. There are bosses 84 (shown dotted in FIG. 2) at opposedends of the crossbar 78. The function of these bosses 84 shall be morefully explained below.

The crossbar 78 rests across the bobbin 12 with the rectangular section82 thereof resting upon a similarly shaped notch 86 in the rear wall 16of the bobbin 12. Only a part of the notch 86 is visible in FIG. 2. Theleg 76 of the first part 72 of the armature 70 is supported by thebobbin 12 in a notch 88 in the front wall 18. Upon being pressed againstthe bobbin 12 the first part 72 of the armature 70 will contact at itsreading portion 90 with the shim 64. The second part 74 of the armature70 is a substantially U-shaped member with one side 92 of the U beingsubstantially longer than the other side 94 thereof. This second side 94of the U has a T-shaped configuration. The crossbar 96 of the secondside 94 is of substantially the same size as the crossbar 78 of thefirst part 72 of the armature 70. The opposed ends of the crossbar 96have apertures 98. When the two crossbars 96 and 78 of the armature 70are placed in registry, the bosses 84 and apertures 98 remain inregistry and keep the reading tips aligned.

The first side 92 is inserted through the bobbin aperture 22 in suchmanner as it will press the shim 64 against the opposed wall of thebobbin aperture 22. The shim 64 is held securely by its boss 66 in theshim aperture 28 of the frustro pyramid section 26 of the bobbin 12.

As shown in FIG. 2, the second side 94 of the second part 74 of thearmature 70 is inclined inwardly. In inserting the second part 74 intothe bobbin l2 and over the first part 72 it is necessary to move back orspring the second side 94 into contact with the crossbar 78 of the firstpart 72 and lock in place by lnunn the engagement of the bosses 84residing in the apertures 98. The pressure of the spring loaded U-shapedsecond part 74 together with the bobbin 12, holds the first part 72 ofthe armature 70 in place. The tip or reading portion 1000f the secondpart 74, taken together with the shim 64 and the reading portion 90 ofthe first part 72 from asubstantially hemispherical reading head 102(FIGS. 3, 4, and 5). The angular relationship of the first part 72 (asdiscussed above) and the frustro pyramidal shape 24 of the bobbin 12serve to permit the relative motion of the reading head with respect toa record wherethe record is disposed on an uneven surface. In thisdesign the reading material which may be for example a record, which maybe for example a label attached to a piece of cloth, will not snag orcatch on any part of the reading portion 102.

The transducer has a housing 104 (as shown in FIG. 1). The housing 104has a top and front wall 106 and 108, respectively, being substantiallyplanar in shape and perpendicular to one another. A third wall 110 isopposed to the first two walls 106 and 108 and lies at an angle thereto.At least a portion of this third wall 110 is curved at its uppermostportion 112 thereof. The purpose of this curved portion 112 is morefully explained below.

Extending perpendicular to the first three walls 106, 108, and 110, andforming therewithin a cavity 114 (FIG. 5) are two side walls 116 and118. These five walls'106, 108, 110, 1 16, and 1 l8 taken togethercomprise a general configuration of the housing 104. In general this isapproximately a gunshape. The lower or muule" end of the housing 104 isclosed by the combination of the bobbin 12 and armature 70. Thecombination of the armature 70 and bobbin 12 are held firmly in placewithout use of glue or other means by fingers 120 (FIG. 4). The fingers120, may be resilient means such as springs or as shown in FIG. 5,molded as an integral part of one of the side walls 1 16.

In the embodiment disclosed, the coil 14 comprises a center tappedtransformer. The output leads 60 of the transformer 14 are connected totabs 52 on the clips 42 connected to the first arm 28 and the center tapis connected to the tab 52 of the clip 42 on the second arm 30 of thebobbin 12. Wires 122 for car rying the information transduced by thetransducer 10 are secured to the arms 28 and 30 and to the clips 42 byscrews 124 (FIG. 5) secured in the apertures 34, 36, and 38. The wires122 form a part of a cable 126. These wires 122 may be secured to theclips 44 by soldering or other similar means rather than screws 124. Ifsoldering is used, the wires 122 may be inserted through the respectiveapertures 32, 34, and 36 and secured to the other side of the clip 42 sothat arms 28 and 30 act as strain relief.

Disposed within the housing 104, and extending perpendicularly to thethird wall 110 is a cylindrically shaped post 128 (FIG. 3). The post 128has therein an axially extending aperture 130 which may be internallythreaded. The third wall 110 has therein an aperture 132 which is aregistry with the aperture 130 of the post 128. This third wall 110 maybe removable for purposes of assembly and repair of the transducer 10and may be secured to the housing 104 by means of a screw 134 or similarmeans. Secured or molded to the post 128 are two metal terminals 135.Wires 122 from the cable 126 may be secured thereto, and may be used asa means for illumination. The means for illumination may be, forexample, an electric lamp 136.

The lamp 136, which resides within the housing cavity 114 adjacent thetop wall 106. The top wall 106 has therein an aperture 138 through whichthe lamp 136 may be seen. The aperture 138 may be in the shape, forexample, of an arrow 140 (FIG. 1). The arrow 140 is intended todirectthe user as to the proper direction of movement for thetransducer. The aperture 138 in the top wall 106 may have therein atranslucent material of clear or colored glass or plastic 142 (FIG. 5).Upon illumination, the arrow 140 indicates an operating state of atransducer 10. As shown in FIG. 3 wires 122 are connected to terminals135 to provide power to the lamp 136.

The terminals may be secured to a section adjacent the post 128 by meansof molding or fixing by glue or similar means. The two wires of the lamp136 are appropriately attached to respective terminals 135.

The cable 126 extends from the transducer 10 to a signal device 144(FIG. 7). This device 144 may be any information receiving device as iscommonly known in the art. The device 144 can, for example, provide asignal to the transducer for lighting the lamp. The signal (not shown)may indicate either an error condition or that the transducer 10 isreceiving information correctly, or, in the alternative, that thetransducer 10 is now in the state ready to receive new infonnation. Thesignal to the lamp 136 may be given from the signal device 144 by manualmeans such as a switch thrown by an operator (not shown) or by automaticmeans either indicating proper operation or an error condition in whichthe transducer should not be used. Such a device 144 is well known inthe art.

The side wall 1 l6 and 1 18 have therein depressions or dimples 146(FIG. 1) at opposed sides of the transducer 10. These dimples 146 areplaced so that the hand 148 of a user may conveniently grasp thetransducer 10 (FIGS. 7 and 11). The thumb 150 and forefinger 152 mayeasily grasp and reside within the dimples 146 of the transducer 10. Thecurved third wall 110 can serve as a support for a third finger 154 ofthe land 148. In normal use, the cable 126 may be held in the palm ofthe hand 148.

The prior art typical electromagnetic transducer as shown in FIG. 8.Such a transducer 200 generally takes the shape of a ring or may besomewhat flattened out, in the manner as shown. The transducer 200 maybe constructed of a solid magnetic material, such as soft iron, nickel,cobalt, steel, ferrite, or similar material. The gap 202 may be providedwhen the material is formed into its particular shape or may be milledfrom the material itself after formation. In the back portion of thetransducer 200 is placed a coil 204 which may be used alternatively forsupplying writing current to the transducer 200 or for receiving orproviding reading current therefrom, depending upon the mode ofoperation. Alternatively, two coils may be provided, one for reading andone for writing purposes. The gap 202 is generally arranged (FIG. 9a)perpendicular to a face or reading surface 206 of the magnetictransducer 200. The transducer 200 may be aligned with a record bearingmedium 208 in such a manner that the face 206 of the magnetic transducer200 is parallel with the direction of relative movement of thetransducer 200 and the record bearing medium 208. The gap 202 is placedperpendicularly to the surface of the record bearing medium 208. The gap202 is placed in such a position as to cause the reading of themagnetized area 210 of the record bearing medium 208. A plurality offlux lines 212 are shown eminating from the left-hand portion of themagnetized area 210, extending about the magnetized area 210, above andbelow it, and closing to the right-hand portion of the magnetized area210. One of these lines of flux 214 is shown entering the magneticstructure 216 of the magnetic transducer 200 at the gap 202. This lineof flux 214 continues through the entire structure 216 and exits fromthe opposite side of the gap 202 from which it entered. Thereafter theline of flux 214 re-enters the magnetized area 210 in order to form aclosed loop.

Flux, like current, follows the path of least resistance. Hence, itenters the magnetic structure 216 because the reluctance of the airspace (or shim, if present) across the gap 202 is greater than thereluctance of the magnetic structure 216.

From this highly simplified representation, only a portion of theavailable flux 212 from the magnetized area 210 is available for entryinto the magnetic structure 216 transducer 200. The strength of the fluxwhich is permitted to enter and which, as a result, induces readoutcurrent in the coil 204 is dependent on the strength of the magnetizedarea 210, the spacing between the record bearing medium 208 and thetransducer gap 202, the width of the gap 202 along the direction oftravel relative to the magnetized medium 206, the length of the gap 202perpendicular to the direction of the travel, the speed of relativemovement between the transducer 200 and the medium 208, and thecomposition of the magnetic structure 216 of the magnetic transducer200.

When the transducer 200 is placed in a tilted position (FIG. 9b) suchthat the face 206 is no longer parallel to the lines of flux 212 theflux exiting from the magnetized area 210 is caused to travel a greaterdistance through the air in order to enter one of the faces of the gap202 in the transducer 200. This will cause a greater reduction in theamount of flux which is permitted to enter the magnetic body of thetransducer 200. The remaining flux is able to close in the air throughthe shorter distance. This failure of flux to enter the transducer 200is due to the lower total reluctance of the air path as compared to along air to pole piece path. This bypassing of the transducer 200 causesa greater reduction in the amount of flux available to the body of thetransducer 200 and thus decreases the amount of signal available at thewinding at the coil 204.

In order to minimize the possibility of such inclination of a gap withrespect to the magnetized surface of a record to be read or recordedupon, it is the general practice in the prior art to rigidly mount atransducer and to control the path of movement of the magnetic medium soas to assure proper alignment and proper positioning of the gap withrespect to the magnetic medium. It should be understood that in an idealcondition (FIG. 9a) write current supplied to the coil 204 is permittedto enter the magnetic medium and produce a greater strength recordingthat is possible in the tilted position (FIG. 9b). Turning now to FIG.10, the transducer 10 of this invention is disclosed having ahemispherically shaped reading portion 102. The gap 158 (defined by theshim 64 and the adjoining edges of the reading portions 90 and 100) ofthe two parts of the armature 72 and 74, respectively, forms an are onthe surface of the hemisphere 102. Much of the difficulties of prior artdevices are avoided by means of this unique design. As referred toabove, rotating of the gap of a prior art transducer relative to arecord causes severe loss of signal strength.

The unique shape of the transducer 10 permits relative rotation betweenthe gap 158 and the record 160 in any one or combination of axes withoutsignificant loss of signal or incurring distortion. Thus, with a tip 102having a radius of one thirty second of an inch and a one-half NRZrecording cell width of 0.0125 inch, a transducer 10 of thisconstruction may read successfully during relative movement (arrow 62)and have relative rotation or positioning with respect to the record 160about an axis which is both perpendicular to the surface of the record160 and to the lines of flux to i 30 (FIG. 10a), with respect to an axisperpendicular to the lines of flux about an axis which is parallel thesurface of the record 160 and parallel to the lines of flux to 145 withrespect to an axis perpendicular to the record surface (FIG. 10b), andabout an axis which is parallel the record surface and perpendicular tothe lines of flux to i 30 with respect to an axis perpendicular to thesurface of the record (FIG. 10c). It is to be understood that the thirdaxis of rotation, which is perpendicular the lines of fiux and parallelthe record 160 (FIG. 100), the axis is substantially proximate therecord. Thus, in FIG. 10c the axis passes through the reading portion102. In addition, relative rotation may be considered the same aspositioning. That is, that the head of this construction and the recordcan assume a fixed position relative to one another about any of theaxes and the transducer will produce a signal having a substantiallyconstant or average strength and shall be free from distortion or noise.One advantage of this design is that the user can hold such a transducerin his hand (FIG. 7) and produce acceptable signals although the handcauses the transducer to move or be positioned about the above-notedaxes. It has been found that the degrees of movement or rotation aresufficient to permit handheld use.

The transducer of this invention represents an improvement over thetransducer described in copending application, Ser.

No. 128,602 by Richard J. LaManna and Alan K. Jensen, entitled MagneticTransducer". It has been observed that the transducer of that inventionis limited in skew rotation (rotation about the axis which isperpendicular to the record and to the lines of flux). In addition it ismuch more complicated in construction in that the gap must be carefullyinscribed on the surface of a keeper over a long length thereof. Inaddition, small cell recording mitigates against flexibility inmovement.

Turning now to other features of the transducer of this invention, itwill be noted that the top wall 106 of the transducer 10 has therein anarrow 140. This arrow 140 indicates the preferred direction of movementas determined by the signal device 144. This direction is dependent uponthe ability of the device 144 to interpret the information received.Transducers in general whether they be magnetic, optical, or the like,are not believed to have such an arrow indication thereon.

Another aspect of the invention is that of dimples 146 (FIG. 1). Thesedimples are located in the first and second side walls 116 and 118,respectively. It should be noted that the first and second side walls116 and 118 lie in imaginary planes parallel to one another. As notedearlier, the general configuration of the transducer 10 is generallygun-shaped. Thus the user of the transducer will naturally grasp thetransducer with the fingers of the hand falling into the dimples 146.The gun-shape of the transducer 10 is also adapted to accommodate thefingers of the hand as shown in FIG. 7.

Turning to another aspect of this invention it should be noted that inFIG. 2 the T-shaped construction of the two-part armature 72 and 74 haveenlarged or T-shaped portions. The armature parts 72 and 74 enable thearmature to be placed together. However, the enlarged area presents sucha greater area that, in relation to any possible spacing or gapping dueto the joining of the two parts together, there is relatively little orno loss of flux at the joining part. This is believed to be an advantageover the prior art devices for ease of construction.

Further, the crossbar portions, the outer portions thereof are employedto secure to the two parts together to form a single armature. Bysecuring the two T portions by the boss and aperture combination theflux paths are not disturbed. Clearly these two parts may be joinedtogether by screwing, gluing, or similar means. However, the boss andaperture combination provides an efiicient means of joining the twoparts together as will be more fully explained below.

The bobbin described herein and shown more clearly in FIG. 2 with itsfmstro pyramidal shaped front wall 24 in assembly with the armatureprovides a guide or protective end as the transducer reading portion 156of the armature 70 is passed over a label 160. See FIGS. 6 and 7. Inassembly of the armature 70 and bobbin 12 of the transducer 10 it shouldbe noted that the second part 74 is inserted into the apertures 22 andthe second part 74 is spring loaded onto the first part 72 and therebyholding both in place and at the same time holding the shim 64 lockedinto position with the boss of the shim 66 fitted into the shim aperture26. Thus, without means of screws, or glue, or other securing means andby virtue of resiliency of joining parts, the entire three elements areheld together. In the same manner, the clips 42 are inserted into thearms 28 and 30. The only means requiring to actually join one element toanother by soldering or screwing is that of the joining of the wires ofthe cable 126 and the wires of the coil 14. The wide surface area of theclips 42 serves to dissipate heat when soldering. It is believed thatmost connectors used in combination with bobbins are of a narrow typehaving a small relative area compared to the wire used in such a bobbinand to the area proximate the bobbin. Thus, heat applied to solder thecoil wires onto such clips or terminals will invariably injure the wire,the insulation, on the wire, and/or the bobbin itself. The clip-on formof these terminals 42 by means of the flange 58 insures quick and easyassembly as of the combination of the armature, bobbin, and shim.

The use of a means of illumination such as the light bulb 136 providesthe means of indication as to when the device is operative or not. Thislighting is controlled by an error or an error signal from the device144 as is commonly known. By this means the user receives an indicationfrom the device 144 which tells the user whether or not the transducer10 should be used. Thus if the light is lit it can be used to indicatethat to the user that the transducer is receiving the information orconversely that the transducer has not received 'the proper informationand the transducer should be moved over the record again or that thetransducer is now ready to receive additional information. By combiningthe light with the arrow the transducer provides an indication of thestate of readiness or usefulness of the transducer and its direction ofuse to the user. Except for the soldering or joining of wires toterminals and the screwing of the curved third wall 112 to thetransducer it should be noted that the entire transducer is assembledwithout means of screwing, soldering, or the like. Thus the bobbinbottom wall 24 of the bobbin 12 serves as the muzzle or transducing endof the transducer 10 and is held in place by the fingers 120 on the sidewalls of the inner side wall of the cavity 114 of the transducer 10.Thus, there is described herein a novel magnetic transducer having manyfeatures applicable to other types of transducers and which iseconomical in construction.

What is claimed is:

l. A handheld magnetic transducer having a plurality of 10 operatingstates comprising:

a. housing means of a configuration facilitating the grasping thereof bythe hand of a user;

b. transducing means housed in said housing means for transducinginformation from a record; and

c indicating means carried by said housing means and including meanswhich is illuminated to indicate that the transducer is operating in apredetermined one of the operating states.

2. A handheld transducer as recited in claim 1 wherein said means whichis illuminated comprises a light bulb.

3. A magnetic transducer of the type including an armature and coilmeans about the armature comprising:

a. a manually held and positionable housing for housing the armature andcoil means;

b. signal means for providing a predetermined signal indicative of theoperating state of the transducer;

0. indicating means carried by said housing and including illuminatingmeans responsive to said signal means to be ilumminated thereby so as toprovide an indication that the transducer is in a predeterminedoperating state.

'4. A magnetic transducer as recited in claim 3 wherein saidilluminating means comprises an electric bulb

1. A handheld magnetic transducer having a plurality of operating statescomprising: a. housing means of a configuration facilitating thegrasping thereof by the hand of a user; b. transducing means housed insaid housing means for transducing information from a record; and c.indicating means carried by said housing means and including means whichis illuminated to indicate that the transducer is operating in apredetermined one of the operating states.
 2. A handheld transducer asrecited in claim 1 wherein said means which is illuminated comprises alight bulb.
 3. A magnetic transducer of the type including an armatureand coil means about the armature comprising: a. a manually held andpositionable housing for housing the armature and coil means; b. signalmeans for providing a predetermined signal indicative of the operatingstate of the transducer; c. indicating means carried by said housing andincluding illuminating means responsive to said signal means to beilumminated thereby so as to provide an indication that the transduceris in a predetermined operating state.
 4. A magnetic transducer asrecited in claim 3 wherein said illuminating means comprises an electricbulb.